The best way to summarize the narrator's internal conflict is
that he is
O
indecisive about killing the old man.
confused by the odd quiet in the house.
afraid he will lose his nerve and run away.
worried his own heart will explode from terror.
O

indecisive about killing the old man.

Explanation:

The other three options like "confused by the odd quiet in the house.", "afraid he will lose his nerve and run away.", "worried his own heart will explode from terror.", the selected sentence says about his inability to take a decision which is a internal conflict that the subject was facing in the given sentence. Also, the sentence, "indecisive about killing the old man." is a great moral conflict the subject has to choose between being good and bad.

faulty parallelism is a construction in which two or more parts of a sentence are equivalent in meaning but not grammatically similar in form.

the correct version of this faulty parallelism in the sentence is:

the hikers knew that the hike was six miles, that it usually required the entire day, and it would not be wise to start after 10: 00 a.m.

the problem is the last sentence, the first two have a basic subject+verb+object structure.

so, to give a proper balance to the structure, or better said, to give a parallel structure, we must write a basic s+v+o structure in all three sentences:

the hikers knew that the hike was six miles, that it usually required the entire day, and it would not be wise to start after 10: 00 a.m.

recommended becuase why did he read the book? becuase it was recommended